ABSTRACT More than 250 million people worldwide have compromised vision and over 10 million have been blinded by some kind of corneal disease or injury, usually involving corneal scarring. Scar presence is a vision threat and currently lacks sufficient treatment. Only a small fraction of these patients will be treated by corneal transplantation. Scar is a condition characterized by the presence of myofibroblasts and the excessive and improper deposition of extracellular matrix components, including type III collagen and fibronectin. Reversing the process, going from opaque to clear, or even preventing scar formation, would be ideal and very beneficial. Recently, a few studies, including our own, have suggested that placement of even an imperfect scaffold into a healing wound may result in healing with a clearer cornea than if the wound was allowed to heal naturally. We have developed a cell-based methodology, with the use of a Vitamin C (VitC) derivative, to generate an extracellular matrix that mimics the corneal stroma. We have also found that growth factors, such as TGF-3, stimulate matrix production without stimulating scar components. We propose to use the stable VitC, together with three different growth factors (TGF-3, PDGF and IGF-II), in order to stimulate human corneal fibroblasts to generate a matrix that mimics the human cornea as closely as possible. We then propose to transplant this optimized matrix into mice that have been humanized' with a human-like immune system. This study will allow the examination of human tissue transplantation in a system that is as close to a human's as animal studies will allow. Three interlocking questions will be tested: 1) How well is the transplanted tissue incorporated into the cornea; 2) How does the cornea react immunologically to a cell-based corneal substitute; and 3) Does the placement of a scaffold result in healing with a clearer cornea than that seen when the cornea is allowed to heal naturally? Relevance to Public Health - Corneal wounding generally results in one of two outcomes-minimal healing, as seen in LASIK surgery, or scar generation, as seen in gaping and penetrating wounds. Our experiments will test whether placement of a cell-based scaffold results in a serious immune response, and if the scaffold may stimulate scar-free healing.